Cord reels are used to retract and dispense cables for electrical devices such as telephones. Within the context of the invention, the cables may be power cables such as extension cables that are used to connect portable electrical appliances to a source of electricity that is remote from the appliance. Alternatively, the cables may be signal cables allowing signals from an electrical appliance to be fed to a desired target. Cord reels of one form or another are well known.
U.S. Pat. No. 6,495,756 discloses a retractable cord assembly comprises a cable having a central carrier and plural conductors helically wrapped about the central carrier.
U.S. Pat. No. 5,535,960 discloses a cord reel assembly for maintaining a length of stationary wire and a length of shielded retractable wire around a spool and dispenses a retractable wire as an attached handset is extended away from assembly, while the stationary wire is concurrently being wound.
WO 2010/146363 discloses a mobile mains-powered appliance i.e. canister-type vacuum cleaner, wherein an electric power cable is wound around rotatable reel, and a socket connector is arranged on an end of the cable.
US 2010/0270413 discloses a rotation-type, single-pull retraction mechanism for e.g. power cable, having a wire material reeled on a wire winding annular wall, where two ends of the wire material pass through two wire-outlet holes.
US 2011/006198 discloses a cable dispensing system for recharging batteries of an electric vehicle, having insulating discs and coils arranged within a housing.
U.S. Pat. No. 6,722,602 discloses a cable management system and method for winding on or letting out a length of cable from a cable support apparatus, in a generally curved, figure eight path, while preventing continuous twisting of a fixed length of cable coupled between the cable support apparatus and a fixed device. The cable support apparatus includes a pair of spools which are arranged at a 45° angle to one another. Cable is alternately wound onto or wound from the two spools as the apparatus is moved in the figure eight path.
U.S. Pat. No. 7,201,342 discloses a signal cable rewinder having two opposing housings in which two independently rewinding discs are disposed. Each of two signal cables is folded once in the middle thereof to form a double-folded member that is wound around the rewinding disc. Both ends of the first signal cable are extended out of the openings of the housings, respectively thus providing two independently retractable and extendable signal cables in a single housing.
One problem which is common to known devices will now be explained with reference to a power extension cable device having a cable wound round a reel in which there is fixed a power socket to which one end of the cable is coupled. A plug is connected to the other end of the cable, thus allowing an electrical appliance such as a power drill to be plugged into the extension cable device, while connecting the plug to a wall socket remote from the appliance thus allowing use of the appliance at a location that is too far from the wall socket for the appliance cable to reach on its own. In such a device, once the appliance is connected to the socket in the extension device, retracting the cable therefrom causes rotation of the socket and with it the cable attached to the appliance. This twists the appliance cable and may cause damage.
The risk of damage is all the more acute when signal cables are extended in a similar manner, since signal cables are very much narrower in diameter than electrical power cables and have multiple cores inside the cable. One common application for retractable cord assemblies for use with signal cables relates to the need to connect portable devices, such as a laptop, to a fixed infrastructure for feeding signals from the portable device to a remote and inaccessible fixture such as a Barco™ projector attached to the ceiling. In this case, a cable from the Barco™ projector is commonly routed to a socket in the floor or to a cable that is accessible from the floor or the like. A signal cable may then be connected from the laptop to the Barco™ extension socket. However, running loose cables along the floor is untidy and so it is becoming increasingly popular to route such cables to a central hub often fixed in the center of a table in a conference room allowing a signal cable to be coupled from the central hub to the laptop.
The present invention is concerned with an improvement to such devices where the need to provide an external signal cable is altogether obviated by providing a retractable signal cable as part of the hub. In this case, it must be withdrawn in order to reach a laptop or other portable device that is typically placed on the conference table and to which the cable in the hub is then coupled. After use, the cable is disconnected from the laptop (or other portable device) and it typically is retracted under spring action back into the hub. Since the hub is a fixed structure, extracting the cable commonly subjects it to twisting as explained above.